You will find out that Caesar has been having headaches and has a brain tumor. There are three ways to complete this quest:
- Having 75 medicine or 9 luck, a Doctor's Bag, and Surgical Tools (bought at New Vegas Medical Clinic, 999 caps).
- Having a Doctor's Bag and finding the Diagnostic Scanning Module (see below).
- Selling Arcade Gannon into slavery as Caesar's private doctor.
Getting the Diagnostic Scanning Module[edit]
You must go to Vault 34. First, stock up on a lot of Rad-X and RadAway, as there is a lot of radiation here. The Vault is northwest of Camp Golf. There are a great deal of ghouls inside.
You have to get to Security Section A which is unfortunately under a flooded hallway. You need two terminal passwords. The first password is in the first flooded area, on a dead vault technician Glowing One under a desk. The second password is through the clinic and into the next flooded area, on the right on another vault technician. Once you have them, go in the door just before the armory, and use the terminal to activate the pump system.
Go to the area where you found the second password, which will now be a closed door. Go through it and make your way to Security Station-A. There is a broken Auto-Doc here with a working Diagnostic Scanning Module. Take it, and return to Caesar and perform the operation.
You will now be sent to talk to Cato Hostilus to initiate the quest Arizona Killer.